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Updated: May 14, 2026
08:23
Finite Element Modelling of a Cellular Electric Microenvironment
Published on: May 18, 2021
Axon terminal polarization induced by weak uniform DC electric fields: a modeling study
Mattia Arlotti1, Asif Rahman, Preet Minhas
1Department of Electronics, Computer Science and Systems, University of Bologna, Cesena, Italy.
Summary
Uniform electric fields from transcranial direct current stimulation (tDCS) impact neuronal excitability. This study estimates axon terminal polarization, finding it converges to Eλ for long branches aligned with the field.
Area of Science:
- Neuroscience
- Computational Biology
- Biophysics
Background:
- Neuronal excitability is modulated by electric fields, notably during transcranial direct current stimulation (tDCS).
- Axon compartment polarization, beyond somatic effects, significantly influences synaptic efficacy.
- Understanding subthreshold electric field effects on axon terminals is crucial for predicting neural responses.
Purpose of the Study:
- To estimate axon terminal polarization under weak, uniform, subthreshold electric fields.
- To investigate the influence of axonal morphology and electric field orientation on polarization.
- To determine the applicability of analytical approximations to real axonal structures.
Main Methods:
- Simulations utilizing 3D morphology reconstructions of axons.
- Employing simplified computational models to analyze membrane polarization.
- Analyzing the relationship between branch length (L) and space constant (λ).
Main Results:
- Axon terminal polarization converges to Eλ for branches where L > 4λ and the field aligns with the branch direction.
- The study quantifies polarization based on specific axonal morphologies and field orientations.
- Conditions for extending analytical approximations to complex axonal structures were identified.
Conclusions:
- Axon terminal polarization in weak DC electric fields is dependent on morphology and field orientation.
- Long, thin axonal branches exhibit predictable polarization patterns under specific field conditions.
- The findings refine our understanding of how tDCS and similar fields affect neuronal function at the axonal level.
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